This invention relates to a sanding system and specifically to a sanding system comprising a deformable pad with an abrasive surface and a holder means by which the pad may be applied to a surface.
Deformable sanding pads have been described in many different forms. Usually the form of that of a expanded foam material with one or more abrasive surfaces. However the foam has been replaced in some formats by a porous fibrous web comprising filaments with abrasive particles adhered thereto. The key feature is deformability such that the surface can be compressed to conform to a non-planar surface, or so that the pressure applied can be varied to change the amount of sanding performed. The pads can be adapted to provide hand gripping means as in U.S. Pat. No. 3,998,012 where the pad is bulky enough to provide some separation between the sanding surface and the hand gripping the pad. It is also known to back rotary abrasive discs with a deformable support, made from a foam rubber pad or the like. A family of such pads designed to be attached to a holder by a hook and loop attachment means is described in U.S. Pat. No. 5,007,128. Here the pad is used to apply a fine sanding powder or slurry rather than itself having an abrasive surface and the surface has a waffle pattern imposed upon it.
In addition to the above art there are many patents describing holders for abrasive sandpaper sheets such that the sheets are stretched over a surface of a holder so that a surface can be sanded without risking the knuckles of the one holding the sandpaper. Typical among these is U.S. Pat. No. 5,337,523 which describes a corner sander with a handle shaped holder. U.S. Pat. No. 2,112,593 describes a block contoured to be easily grippable and adapted to trap a sheet of sandpaper and stretch it over a flat surface of the block. U.S. Pat. No. 5,168,672 describes a similar device with a rather more complex system for retaining the sheet in place. U.S. Pat. No. 5,662,519 describes a flexible elongated gripping block with a sanding surface adapted to receive and support a sheet of sandpaper attached thereto by a pressure sensitive adhesive or a hook and loop fastener system. Other patents describing a system with an associated gripping means include U.S. Pat. No. 2,280,767 (where the abrading means is provided by abrasive blocks), U.S. Pat. Nos. 5,512,010; 5,383,308; 5,172,524; 5,054,248; 2,400,928; 1,844,996; 1,599,906; and 1,067,280.
However the sytems providing a holder usually have a substantially rigid support for a sheet of sandpaper or else an extension of a foam block providing the gripping means. Mechanical gripping of a deformable pad is not straightforward precisely because it is deformable. In use the retention of the pad within the holder becomes difficult as the intensity of the sanding increases. In addition making the abrasive pad deformable and giving it an abrasive surface implies that the pad is to be thrown away after use thereby adding to the cost significantly.
A sanding system has now been devised in which the sanding pad is deformable and yet can be retained in a holder securely, and which can provide a plurality of abrading surfaces. Moreover the retention means does no damage to the abrading surfaces meaning that the pad can be removed and replaced a plurality of times without compromising the security with which the pad is held.